GRIMSBY, U.K. – The Royal Air Force says none of its planes were responsible for the “sonic boom.” So what was it?

GRIMSBY, U.K. – The Royal Air Force says none of its planes were responsible for the “sonic boom.” So what was it?

Residents of Grimsby heard what sounded like a large explosion at about 7pm on Wednesday.

Initial fears that there had been an explosion were quickly allayed and authorities quickly confirmed that it was a sonic boom from an RAF plane.

Some thought the sonic boom occurred in outer space…

But no, it was an RAF plane:

WWN learned that The Ministry of Defence (MOD) is carrying out a low-flying operation named “Exercise Lightning Force” in the Grimsby area.

Squadron Leader Anne Jarman, based at Headquarters Air Command, said the noise was caused by an RAF aircraft, part of’ “fast jet units.” She went on to say that a sonic boom occurs when an aeroplane breaks the sound barrier and the noise that you hear is the shockwave of area around the aircraft.

When local Grimsby residents heard the boom, they all ran inside, and hid under tables and beds.

“Hearing a sonic boom is something that some find ‘cool”, but many residents were frightened. We had to calm our citizens,” said Mayor Tom Perklin.

“These things do happen and it is certainly not something that people should be scared about.”

Julie Siploin, who lives in nearby Laceby, said: “I heard a big bang and the whole house shook. “I looked out of the window but all I saw was a plane flying over.”

Emma Lingard, of Healing, was tending to her horse in Immingham when the bang occurred. “I heard a loud clatter on the roof and some pheasants flew off, so I thought it was an animal,” she said.

“I jumped and the horse jumped. I walked out of the stable and couldn’t see anything.

“When I returned to the car, where my son, Tom, was, he said the car had shook.